The securing of a cutting tool in a tool holder of a machine tool has presented problems in the cutting tool industry. The tool holder typically has a tapered shank which is secured to the machine tool and a cavity for receiving the cutting tool. The cutting tool has a shank or tool body insertable into the cavity and an opposed end having at least one cutting insert assembly.
The cutting tool shank is generally secured in the cavity through the use of a machine tool collet which is compressible about the shank of the cutting tool. A typical machine tool collet is described in Hoyle et al, U.S. Pat. No. 4,705,439.
The collet is typically made with a series of spaced-apart slits around the circumference of the collet, which enable the collet to expand or contract around the cutting tool to thereby provide a secure fit.
Although collets are effectively employed for relatively low speed cutting operations, problems arise when trying to secure a cutting tool with a collet in machine tools operated at above 10,000 rpm. This is because the inner surface of the fingers formed between the adjacent axial slits do not provide full face to face contact with the shank of the cutting tool. In most cases, only single line or double line contact is made and therefore the maximum compressive force provided by a collet against the shank is often less than desirable for securing a cutting tool under high speed operations.
Applicant has discovered a unique system for locking a cutting tool in a tool holder in which the use of collets is eliminated and the compressive force generated on the cutting tool shank greatly exceeds that provided by typical collets.
It is therefore an object of the invention to provide a device for locking a cutting tool in a tool holder without the use of a machine tool collet.
It is another object of the invention to provide a chuck which employs angled bearings which enables a rotatable ring to generate a compressive radial force for locking the cutting tool within a tool holder.
It is a further object of the invention to provide a chuck which provides a 360.degree. radially centered compressive force in the direction of the shank of the cutting tool and also enables axial adjustment of the cutting tool within the tool holder.
It is a still further object of the invention to provide a chuck which exerts both a 360.degree. radially centered compressive force on the cutting tool and also an axial force in the direction of the tool holder to thereby maximize the locking force acting on the cutting tool to thereby eliminate deflection.